Apr. 26,1924 Pecan Scab and Sources of Early Spring Infections 327 
thought to be safe to spray on account of probable injury to the tender foliage. 
The result of this spraying experiment was a complete failure as far as control 
was concerned. In spite of six applications of spray, of which five were with 
standard strength Bordeaux mixture, the disease completely destroyed the crop. 
This orchard was sprayed four times with Bordeaux mixture during the previous 
season and it is thought that twig infections of that year played a very minor 
part in causing the primaty infections of the past year. 
As a contrast to the Quincy, Fla., experiment, the results are given below of a 
spraying test at Thomasville, Ga., on the same variety. This orchard had been 
sprayed for two years previous, and the ground was carefully plowed during 
late winter so that all leaves, petioles, and shucks were buried under the soil. 
The disease did not appear in this orchard until about the first of June. An 
application of spray at this time was highly desirable but was postponed until 
June 6 on account of rainy weather. The second application was made July 3, 
and the third and last one August 3. As a result of this work, approximately 
89.6 per cent of the crop of the Bordeaux-sprayed trees was saved. The control 
trees in this orchard matured some good nuts, but 56 per cent of the crop fell 
before maturity. Of those nuts remaining on the trees until harvest 20 per cent 
were either totally bad or faulty. The sprayed nuts averaged 64 to the pound, 
while the unsprayed ones averaged 74. It is not thought that the weather 
conditions at Thomasville were more favorable for a spraying experiment than 
at Quincy, Fla., as it was unusually rainy and cloudy during the season. In¬ 
cluding days with a trace, rain fell on 19 days in May, 24 days in June, 21 days 
in July, and 15 days in August at Thomasville. No record of the rainfall at 
Quincy, Fla., is available. 
A standard spray schedule for pecan scab has not yet been definitely estab¬ 
lished. A spray schedule that produces satisfactory results one season often 
proves to be entirely ineffective another one. Very satisfactory results were 
procured at Dewitt, Ga., in 1922 by applying the spray on the following dates: 
May 1, May 17, June 6, June 28, July 19, and August 19. A similar schedule 
followed during the season of 1923 in the same orchard did not control the disease 
satisfactorily. At Baconton, Ga., in 1922, excellent results were obtained by. 
applying spray on the following dates: June 13, July 6, July 27, and August 23. 
In 1923, despite the fact that spraying in this orchard was begun a month earlier 
and two more applications were made than in 1922 the results were not satis¬ 
factory. 
As a general recommendation in the light of our present knowledge and experi¬ 
ence, the first application of a protective spray should be made immediately after 
the nuts have set. Later applications should be made at intervals of two or 
three weeks. The weather conditions, the amount of scab in the orchard the year 
previous, the relative susceptibility of different varieties, and the attention paid 
to sanitation are factors that must govern the number and time of application. 
DORMANT SPRAY 
In an endeavor to eliminate the twig lesions as sources of the early spring 
infections, Bordeaux mixture containing 8 pounds of bluestone and 8 pounds of 
stone lime to 50 gallons of water and lime sulphur solution prepared by adding 
6 gallons of the concentrated solution (32 to 33° B.) to 42 gallons of water have for 
three successive years been applied as dormant sprays. The time of application 
was in all cases delayed until a few days before or even after the buds begin to 
swell. While it appears that a strong fungicide would kill the hold-over stromata, 
only slight evidence has been secured by the writer favorable to the use of the 
winter spray. 
